1. Field of the Invention
The present invention relates to a selfcleaning collecting device for removing vapors and solid particulates from a gas stream.
2. Description of the Prior Art
The prior art includes a variety of collecting arrangements for removing noxious vapors and solid particulates from a dirty gas stream generated by the various metal working and chemical processes used in automotive plants, foundries, and the like.
U.S. Pat. No. 2,966,958 discloses a typical collecting device wherein noxious vapors and larger particulates are removed from a dirty gas stream by passing the gas stream through a porous media flooded with a liquid which coalesces with the vapors and entrains the particulates so they can be removed by separating the liquid from the gas stream. While this type of arrangement has been satisfactory in many applications, experience has indicated it usually is most effective where the clean air is discharged into the atmosphere away from the work area as it is primarily intended to remove larger particulates having a diameter in excess of 1 micron. Thus, this type of arrangement would generally be inappropriate where it is desired to recycle the air within a plant to save heating or cooling of the air where a substantial portion of the particulates smaller than 1 micron would still be entrained in the air.
The electrostatic precipitator shown in U.S. Pat. No. 3,016,980 represents one method of cleaning the air in a factory prior to recycling it within the plant. In that arrangement, the dirty gases are circulated through one or more collecting cells having a plurality of spaced parallel collecting plates which are charged to attract oppositely charged particles in the dirty gases as they flow through the cell between the collecting plates. In the typical plant application, a plurality of cells are secured to a grid-like frame to form a bank of side-by-side cells sized according to the air cleaning requirements of the installation. While this approach has proven to be extremely effective in many applications, when it is used to remove the particulates and oil vapors generated during flame cutting and various die casting operations, the rapid agglomeration of the particulates resulting from those processes on the collecting plates tends to clog up the cells, and localized accumulations of liquid on the plates often lead to excessive arcing within the individual cells. Consequently, where this type of arrangement has been used to clean the gases resulting from those processes, it has generally been necessary to construct a very large installation to maintain the air flow through each of the cells at a level low enough to prevent these problems.